Model Identification And Behavioral Characteristics Measurement Of Shape Memory Alloys

SMA (shape memory alloy) has a reasonable mechanical property, its shape will be changed in electrically-heated. In the robot research field, because of its big power weight ratio, small volume and simple structure, SMA can be used to actuate its joint. Due to the complex mechanism, the performance of the actuator depends on the dynamic model of SMA. In order to identify and control the SMA.One part of the work in this thesis is the construction of the measurement platform of SMA.The constant or the variable strain control can be achieved by using FAULHABER linear motor LM1247, which can be used to measure the strain and stress of SMA by the way; SMA is put into the transformer oil to get a temperature-controllable environment to support the research of SMA;It is implemented that serial communication with the FAULHABER servo unit, the temperature control and the real-time data collection based on dSPACE.The other part of the work is the study and identification of SMA. dSPACE can realize the data interaction with external environment using the S-function in Simulink;The data will be recorded by ControlDesk, and 3D figure of the temperature, strain and stress of the SMA will be plotted with the help of the Matlab;Linear model and nonlinear model of SMA are implemented using system identification theory in room temperature, and the model is be verified by experiment. More detail,the linear model is represented in transfer function, which reflects the relationship between the input and output signal of SMA, and Its nonlinear model is got by the pseudo-random binary sequence.